Air jet weaving looms of the kind mentioned above are used to manufacture particularly fine fabrics. The trend in weaving is toward finer and finer fabris, i.e. material with fine thread and a high weft density. For this purpose it is known to extend the spreader table as far as possible into the weft insertion channel. See U.S. Pat. Nos. 4,919,171 (Dornier) and 4,951,717 (Riezler).
In the processing of such fabrics it became apparent that a strong contraction takes place, especially along the margin area of the web, i.e. the margin the fabric contracts more than the central area of the fabric, leading to an undesirable shrinkage of the fabric width so that the running characteristic is impaired due to breakage of warp threads in the margin area. This also reduces the quality of the fabric and hence the effectiveness and productivity of the machine. For these reasons it has been impossible to exceed a lower limit with regard to fineness of the yarn and the weft density.